Aqueous based personal washing cleanser

ABSTRACT

An aqueous based personal washing product is disclosed which when used has good cleaning ability and is particularly mild to the skin. The free flowing liquid product, containing a selected blend of surfactants and emollients, including long chain fatty acids, free isethionate salts and acylisethionates is particularly adapted for facial washing.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is in the field of aqueous based, surfactant containing,mild cleansers, providing good foaming, moisturizing and cleaning,without excessive harshness.

The use of moisturizers in traditional washing bars is severely limitedby processing constraints. Usually bars with a high content ofmoisturizers are sticky and cannot be easily stamped. Some of thedifficulties of formulating a good personal washing product with highlevels of moisturizers were eliminated by using liquid products to avoidthe stamping problem.

Moisturizers have also been found to inhibit lathering. However,lathering is desirable for washing products. Further, a highconcentration of moisturizers while being desirable for mildness andskin benefit has a tendency to de-stabilize liquid products.

It was thus desirable to formulate an aqueous based product containinghigh levels of moisturizers in combination with high levels of mildsurfactants to result in a substantially stable personal washing productwhich is exceptionally mild to the skin; and having excellent latheringcharacteristics which also leaves the skin feeling smooth, silky, andmoisturized.

2. Description of the Art

Japanese Patent JP-A-63/243,200 discloses a detergent compositioncontaining a combination of specified acyl isethionates, higher fattyacids and N-acylglutamic acid salts. U.S. Pat. No. 4,556,510 and4,617,148 both disclose liquid soaps containing polymeric thickenersalong with several other surfactants including optionally sodium cocoylisethionate. U.S. Pat. No. 4,495,079 discloses a therapeutic facial skincleanser composed of selected surfactant mixtures and activeingredients.

There have been many different approaches to the problem of producing anaqueous based mild cleanser containing high levels ofemollients/moisturizers together with combinations of mild surfactantshaving good viscosity, good stability, and high latheringcharacteristics. None of these approaches has been completelysatisfactory. In many cases, stability is sacrificed to improveviscosity, or mildness is de-emphasized to improve cleaning ability ormoisturizing is minimized to improve lathering.

Accordingly, it is an object of the present invention to provide afluid, aqueous based cleansing and moisturizing product characterized byits mildness, good lathering properties acceptable viscosity andstability. This is accomplished while substantially eliminating man ofthe problems of the art. Other objects and advantages will appear as thedescription proceeds.

SUMMARY OF THE INVENTION

The attainment of the above objects is made possible by this inventionwhich includes an aqueous based composition containing long chainacylisethionates, free isethionate salts, long chain fatty acids andmoisturizing agents in specified amounts and ratios.

The inventive composition has the advantages of mildness, goodmoisturizing, good lathering, and excellent long term stability. Otherstandard ingredients such as polymeric thickener, preservatives,co-surfactants, sequestrants, foam boosters, and the like may also beemployed to advantage. The formulation may contain the following generalingredients provided an appropriate viscosity is achieved:

    ______________________________________                                        Ingredients        %                                                          ______________________________________                                        long chain acylisethionate                                                                       3-20%                                                      long chain fatty acids                                                                           2-15%                                                      emollient/moisturizer                                                                            2-15%                                                      co-surfactant      2-20%                                                      preservative       0.1-1%                                                     sequestrant        0.01-0.1%                                                  standard additives 3-15%                                                      water              balance                                                                       100                                                        ______________________________________                                    

A critical component of the formulations of this invention is a non-soapanionic surface active agent. Particularly suitable agents for thisinvention are the C8-C₂₂ acyl isethionates. These esters may be preparedby the reaction between alkali metal isethionate and mixed aliphaticfatty acids having from 8 to 22 carbon atoms and an Iodine Value of lessthan 20. In one embodiment of the invention at least 75% of the mixedfatty acids should preferably have from 12 to 18 carbon atoms and up to25% should have from 8 to 10 carbon atoms.

Another suitable syndet is that of alkyl glycerol ether sulfonate. Alkylchains for this surfactant are from C₈ to C₂₂, preferably C₁₀ to C₁₈.

Free fatty acids of 8-22 carbons are desirably incorporated within thecompositions of the present invention. These fatty acids are present tooperate as lather enhancing agents and as skin feel, lubricity, andcreaminess enhancers. The agents may be selected from fatty acids ofcarbon atoms numbering 8-18 in an amount up to about 15% by weight ofthe composition. The most important agent is a stearic acid/palmiticacid mixture. Levels of these acids can range from 1% up to 15%. Acombination of principally a palmitic and stearic acids about 45%stearic and 55% palmitic is preferred.

Emollients/Moisturizers

Moisturizers are included to provide skin conditioning benefits and toimprove the mildness of the product. The selection of the levels andtypes of moisturizers to be incorporated into the product is done insuch a manner as not to adversely affect the stability of the product orits in-use characteristics, and still deliver good moisturization andlather.

The term "moisturizer" is often used synonymously with the termemollient, and is then meant to describe a material which imparts asmooth and soft feeling to the skin surface.

One way of reducing water loss from the stratum corneum is to deposit onthe surface of the skin a layer which reduces the rate of evaporation.Another method is to add hygroscopic substances, which will retainwater, to the stratum corneum, to make this water available to thestratum corneum.

Both types of moisturizers as well as mixtures of these are operative inthe present invention. Some examples of moisturizers are long chainfatty acids, liquid water-soluble polyols, glycerin, propylene glycol,sorbitol, polyethylene glycol, ethoxylatedpropoxylated ethers of methylglucose and ethoxylated/propoxylated ethers of lanolin alcohol.

The moisturizers useful in the present invention are used at a level ofabout 5% to 35% by weight of the composition. The preferred and morepreferred levels of moisturizers are, respectively, 5% to 30% and 8% to20%. The most preferred moisturizer is a mixture of propylene glycol anda combination of stearic and palmitic acids having a ratio of glycol toacid of 1:3 to 5:1. The moisturizer, at the above levels, providessuperior moisturization. The high level of moisturizer can provideenhanced mildness.

The moisturizer to soap ratios when soap is used are preferably 7 to 1and, more preferably, 4 to 1.

Other moisturizers are compounds found naturally in the stratum corneumof the skin.

Moisturizers also include petrolatum, mineral oil, beeswax, silicones,lanolin and oil-soluble lanolin derivatives, saturated and unsaturatedfatty alcohols and various animal and vegetable oils.

Soaps

Soaps may optionally be included in the compositions of this inventionas a structurant.

Soaps can be used at levels of preferably about 5% and most preferablyat a level of about 2%. The soaps may be added neat or made in situ viaadding a base, e.g., NaOH, to convert free fatty acids.

Free sodium isethionate in an amount of about 1% to 7& affects stabilityand viscosity and may also affect mildness.

Standard additives such as coloring agents, opacifiying agents e.g.TiO₂, thickeners e.g. carbopols may be used with the invention invarying amounts to insure appropriate benefits.

Sequestering agents such as EDTA, ethylene diamine tetraacetic acidtrisodium salt or EHDP [disodium (1-Hydroxyethylidene) biphosphate] ormixtures of these in amounts ranging from 0.01 to as high as 1.0%preferably about 0.01 to 0.05% may be used.

Preservatives such as antimicrobials or antimold/fungus agents may beused. Examples of these are methyl paraben (p-hydroxymethylbenzoate);propyl paraben (p-hydroxypropylbenzoate); and Dowicil 200[N-(3-chlorallyl) Hexaminium chloride]. These and other similarmaterials may be used in amounts of about 0.1% to about 0.5% and may beused separately or in combination.

Antioxidants such as, for example, butylated hydroxytoluene (BHT) may beused advantageously in amounts of about 0.01% or higher if appropriate.

A number of anionic, nonionic, cationic and amphoteric surfactants maybe employed as the co-active. In copending case Ser. No. 340,185 filedon Apr. 19, 1989, co-active combinations in bars with acyl isethionatesare disclosed. Among suitable anionic co-actives are the alkyl ethersulfates, alkyl ether sulfonates, sarcosinates, sulfosuccinates,taurates and combinations thereof. Among suitable amphoteric co-activesmay be included alkylbetaines, amidropropyl betaines, amidopropylsultaines and combinations thereof.

The relative amounts of modified isethionate esters to co-actives willrange in the weight ratio of about 20:1 to about 1:1, preferably fromabout 5:1 to about 2:1, optimally about 3:1.

Alkyl ether sulfates of the present invention will be of the generalformula R--O(CH₂ CH₂)_(n) OSO₃ --M⁺ wherein R ranges from C₈ -C₂₀ alkyl,preferably C₁₂ -C₁₅ alkyl, n is an integer from 9 to 40, preferably from10 to 20, optimally about 12, and M⁺ is a sodium, potassium, ammonium ortriethanolammonium cation. Typical commercial co-actives of this varietyare listed in the Table below:

    ______________________________________                                                                 Physical                                             Trademark                                                                             Chemical Name    Form     Manufacturer                                ______________________________________                                        Alkasurf                                                                              Sodium Laureth Sulfate                                                                         Paste    Alkaril                                     ES-60                                                                         Cycloryl                                                                              TEA Laureth Sulfate                                                                            Paste    Cyclo                                       TD                                                                            Standapol                                                                             Sodium Laureth-12 Sulfate                                                                      Liquid   Henkel                                      125-E                                                                         Cedepal Sodium Trideceth Sulfate                                                                       Paste    Miranol                                     TD407MF                                                                       ______________________________________                                    

Alkyl ether sulfonates may also be employed for the present invention.Illustrative of this category is a commercial product known as AvenelS-150 commonly known as a sodium C₁₂ -C₁₅ Pareth-15 sulfonate.

Another co-active type suitable for use in the present invention is thatof the sulfosuccinates. This category is best represented by themonalkyl sulfosuccinates having the formula: RO₂ CCH₂ CH(SO₃--Na⁺)COO--M⁺ ; and amido-MEA sulfosuccinates of the formula: RCONHCH₂CH₂ O₂ CCH₂ CH(SO₃ --M⁺)CCO--M⁺ ; wherein R ranges from C₈ -C₂₀ alkyl,preferably C₁₂ -C₁₅ alkyl and M⁺ is a sodium, potassium, ammonium ortriethanolammonium cation. Typical commercial products representative ofthese co-actives are those listed in the Table below:

    ______________________________________                                                                   Physical Manu-                                     Trademark                                                                             Chemical Name      Form     facturer                                  ______________________________________                                        Emcol   Disodium Lauryl    Solid    Witco                                     4400-1  Sulfosuccinate                                                        Schercopol                                                                            Disodium Cocoamido MEA                                                                           Liquid   Scher                                     CMSNa   Sulfosuccinate                                                        Emcol   Disodium Myristamido MEA                                                                         Paste    Witco                                     4100M   Sulfosuccinate                                                        Schercopol                                                                            Disodium Oleamido MEA                                                                            Liquid   Scher                                     Varsulf Disodium Ricinoleamido MEA                                                                       Solid    Scherex                                   S13333  Sulfosuccinate                                                        ______________________________________                                    

Sarcosinates may also be useful in the present invention as a co-active.This category is indicated by the general formula RCON(CH₃)CH₂ CO₂ --M⁺,wherein R ranges from C₈ -C₂₀ alkyl, preferably C₁₂ -C₁₅ alkyl and M⁺ isa sodium, potassium, ammonium or triethanolammonium cation. Typicalcommercial products representative of these co-actives are those listedin the Table below:

    ______________________________________                                                                 Physical Manu-                                       Trademark   Chemical Name                                                                              Form     facturer                                    ______________________________________                                        Hamposyl L-95                                                                             Sodium Lauroyl                                                                             Solid    W. R. Grace                                             Sarcosinate                                                       Hamposyl TOC-30                                                                           TEA Cocoyl/  Liquid   W. R. Grace                                             Sarcosinate                                                       ______________________________________                                    

Taurates may also be employed in the present invention as co-actives.These materials are generally identified by the formula RCONR'CH₂ CH₂SO₃ --M⁺, wherein R ranges from C₈ -C₂₀ alkyl, preferably C₁₂ -C₁₅alkyl, R' ranges from C₁ -C₄ alkyl, and M⁺ is a sodium, potassium,ammonium or triethanolammonium cation. Typical commercial productsrepresentative of these co-actives are those listed in the Table below:

    ______________________________________                                                                 Physical                                             Trademark                                                                              Chemical Name   Form     Manufacturer                                ______________________________________                                        Igepon TC 42                                                                           Sodium Methyl Cocoyl                                                                          Paste    GAF                                                  Taurate                                                              Igepon T-77                                                                            Sodium Methyl Oleoyl                                                                          Paste    GAF                                                  Taurate                                                              ______________________________________                                    

Within the category of amphoterics there are three general categoriessuitable for the present invention. These include alkylbetaines of theformula RN⁺ (CH₃)₂ CH₂ CO₂ --M⁺, amidopropyl betaines of the formulaRCONHCH₂ CH₂ CH₂ N⁺ (CH₃)₂ CH₂ CO₂ --M⁺, and amidopropyl sultainessultaines of the formula RCONHCH₂ CH₂ N⁺ (CH₃₂ CH₂ SO₃ --M⁺, wherein Rranges from C₈ -C₂₀ alkyl, preferably C₁₂ -C₁₅ alkyl, and M⁺ is asodium, potassium ammonium or triethanolammonium cation. Typicalcommercial products representative of these co-actives are found in theTable below:

    ______________________________________                                                                 Physical                                             Trademark Chemical Name  Form     Manufacturer                                ______________________________________                                        Lonzaine C                                                                              Cocamidopropyl Liquid   Lonza                                                 Betaine                                                             Lonzaine CS                                                                             Cocamidopropyl Liquid   Lonza                                                 Hydroxysultaine                                                     Lonzaine 12C                                                                            Coco-Betaine   Liquid   Lonza                                       Schercotaine                                                                            Myristamidopropyl                                                                            Liquid   Lonza                                       MAB       Betaine                                                             Velvetex  Oleyl Betaine  Paste    Henkel                                      OLB-50                                                                        ______________________________________                                    

Within the broad category of liquid co-actives, the most effective arethe alkyl sulfates, alkyl ether sulfates, alkyl ether sulfonates andsulfosuccinates.

Viscosity

Viscosity of the formulation is measured with a Brookfield cone andplate H.B.D.V. II viscometer at 25° C. and a shear rato at 2 min of s⁻¹.The viscosity of the compositions of the invention will vary from about100 cps to about 30,000 cps or higher if desirable. Preferably, about10,000 cps to 15,000 cps.

Lather

Lather evaluations are done by applying a two gram sample to the hands,followed by applying six milliliters of water. The hands are then placedpalm to palm and rotated five times in a circular motion in order todissolve the product. The product is then "worked up" by rotating thehands ten times. The resulting lather is measured by immersing the handsin a distilled water bath and lowering a funnel, whose neck has beenfitted with a graduated cylinder, over the hands, so that the volume oflather can be measured.

Selected combinations of acyl isethionate and stearic/palmitic acid showimproved lathering.

The following examples are designed to illustrate, but not to limit, thepractice of the instant invention. Unless otherwise indicated, allpercentages are by weight.

EXAMPLE I

A typical aqueous based formulation according to the instant inventioncontains the following ingredients in the indicated amounts:

    ______________________________________                                        Ingredients             %                                                     ______________________________________                                        Sodium Cocoyl isethionate                                                                              11%                                                  Stearic acid             8%                                                   Propylene glycol         10%                                                  Sodium isethionate       5%                                                   TEA lauryl sulfate       5%                                                   Sodium soap (82/18)      2.5%                                                 Sodium alkylbenzene sulfonate                                                                          2%                                                   Fragrance                0.4%                                                 Methylparaben            0.20%                                                Propylparaben            0.10%                                                Dowicil 200              0.10%                                                EDTA                     0.02%                                                EHDP                     0.02%                                                BHT                      0.008%                                               Water to                100.00%                                               ______________________________________                                    

Process

A batch of the formulation of the invention is conveniently prepared asfollows (some of the numbers are approximate since commercial solutionsvary in content.);

A submix is first prepared by charging 3,200 lbs. of propylene glycol toa tank with agitation. 2,019.20 lbs. of sodium isethionate is added withslow speed agitation. 1,174.40 lbs. of a slurry containing 645.9 lbs. ofsodium alkyl benzene sulfonate is then added and mixing is continued toinsure uniformity. 4,000 lbs. of a 40% solution of triethanolaminelauryl sulfate is then added and mixed until uniform at a temperature ofabout 80° to 90° F. This submix is then set aside for future use.

13,577.76 lbs. of deionized water is heated and charged to the mainmixing tank and is maintained at about 180 degrees F. The previouslyprepared submix is then slowly added with slow speed agitation. 6,329.6lbs. of a commercial preparation of sodium cocoyl isethionate is thenadded. This material contains 55% sodium cocoyl isethionate; 30% longchain fatty acids; 8% sodium isethionate and 7% miscellaneous; 768 lbs.of soap; 64 lbs. of methyl paraben, 32 lbs. of propyl paraben, 16.32lbs. of EDTA and 10.56 lbs. of EHDP are added with mixing at about 5minute intervals. 601.60 lbs. of stearic acid is then added andagitation is increased as necessary to achieve uniformity. The entirebatch is then mixed at 175° to 180° F. to insure uniformity. The batchis then slowly cooled to about 115° F. 32 pounds of Dowicil is mixedinto 65 lbs. of cold deionized water and this mixture is added to thebatch. A previously prepared homogeneous fragrance mix composed of 128lbs. of perfume and 2.56 lbs. of BHT are added and mixed into the batch.The entire batch is then mixed and cooled to reach a suitable viscosity.

Thickener slurries may, of course, optionally be used at appropriatepoints. These slurries may contain suitable materials such as polymerse.g. carbopol, gums and the like.

EXAMPLE 2

This Example illustrates the equivalency in mildness between acomposition of the invention A and a 50% aqueous slurry of a commercialnon soap detergent bar B. The percentages of B are approximate. Table Ilists the two compositions.

                  TABLE I                                                         ______________________________________                                        Formulations                                                                                 A % wt./wt.                                                                             B % wt./wt.                                          ______________________________________                                        Sodium Cocoyl Isethionate                                                                      10.95       25.0                                             Stearic Acid*    8.01        10.0                                             Na Soap (82/18)  2.40        5.5                                              Sodium Alkylbenzenesulfonate                                                                   2.02        1.0                                              Sodium Isethionate                                                                             5.09        2.4                                              TEA Lauryl Sulfate                                                                             5.00        --                                               Propylene Glycol 10.00       --                                               Cosmedia Guar C-261                                                                            0.50        --                                               (guar gum/thickener)                                                          Methylparaben    0.20        --                                               Propylparaben    0.10        --                                               Dowicil 200      0.10        --                                               Viscasil 60M (silicone)                                                                        1.00        --                                               Perfume          0.10        0.5                                              Lower Fatty acid --          1.5                                              Miscellaneous solids                                                                           --          1.7                                              & electrolytes                                                                Water            To 100.0    To 100.0                                         ______________________________________                                         *C.sub.14 = 3%; C.sub.16 = 50%; C.sub.18 = 47%                           

Both formulations were tested by Flex Wash. Table II lists the Flex Washoutcome which confirms the equivalently mild behavior of Formulation Ato a 50% slurry of a commercial bar whose major ingredient is sodiumcocoyl isethionate.

                  TABLE II                                                        ______________________________________                                        Flex Wash Test                                                                Sample       Mean Scores*                                                     Erythema     Endpoint Erythema                                                                           Mean Rank                                          ______________________________________                                        A            1.385         13.62                                              B            1.385         13.38                                              ______________________________________                                        Statistical Analysis  P = 0.9580                                              Rank Scores:                                                                  (Wilcoxon 2 sample)                                                           ______________________________________                                         *Mean end point scores are the mean of the evaluation scores at which the     first arm received a grade "2" or greater erythema score or at the            completion of nineteen washes.                                           

The Flex Wash Test

The Flex Wash procedure consists of four daily 60 second washes of theantecubital fossa (flex area of elbow). This method was designed toproduce erythema quickly. Erythemal response varies only slightly withtemperature and humidity fluctuations making the protocol suitable foryear round testing.

Approximately 15 panelists were used as the test population. Panelistflex areas must be free of any skin condition (eczema, dryness,irritation, cuts or abrasions). Anyone taking antihistamines,anti-inflammatory drugs or topical, oral or injectable cortisone on aregular basis was excluded from the study. The panel was divided intotwo subgroups which were balanced for left handedness. Group I wasassigned composition "A" for the left flex and "B" for the right flex.Group II reversed the order.

Following an evaluation, the panelist was instructed o moisten the leftflex area. A sponge was dampened with tap water (100 ppmcalcium/magnesium ions). A fixed amount of test product is applied tothe sponge. The "dosed" sponge was placed in the panelist's right hand.The panelist then washed the left flex area for exactly 60 seconds(approximately 120 strokes). Thereupon, the flex was rinsed and patteddry. This washing procedure was repeated on the right arm with theappropriate composition. Washing by this procedure was repeated 4 timesdaily for four days and 3 times on the fifth day for a total of 19washes. Treatment times were scheduled 1.5 hours apart. Each test sitewas evaluated immediately prior to washing and 4 hours after the thirddaily wash.

One trained assessor evaluated test sites prior to each wash and 4 hoursafter the third wash of the fifth day for a total of 20 evaluations. Thegrading scale was as follows:

0--no erythema

0.5--barely perceptible erythema

1--mild spotty erythema/no edema

1.5--mild/moderate erythema/with or without edema

2--moderate confluent erythema/with or without edema or vesiculation

Each site was treated in the prescribed method until a grading of "2" orgreater was attained or 19 washings had been completed. When a score of"2" or greater was attained the treatment was discontinued on that flex.The final score was then carried through for all remaining evaluations.The remaining flex was washed until either a grading of at least "2" or19 treatments were attained, whichever was first. In this Example, thefinal grading is the sum total of grade scores for 20 assessments perpanelist averaged over the scores from all panelists. Thus,theoretically the average score could range from 0 to 38; the lowervalue indicating absolutely no skin irritation with the latter beingsevere. In practice, scores generally range from 15 to 30.

Arm Wash

The objective is to compare the levels of irritation and/or dryness oftwo products on skin by assessing the changes in skin condition duringexaggerated use conditions. Changes are assessed both visually andinstrumentally.

The subject/panelist is in the age group of 18-55 years. The subjectmust have been screened for soap sensitivity and found to be sensitiveto the screening solution. The target site must be free of cuts andabrasions and have a grade "0" for both erythema and dryness following atwo week preconditioning period.

The subject must refrain from using creams, lotions or other types ofmoisturizing products over the target body area (the forearms)throughout the duration of the test.

Subjects with allergies to soap and fragrances, a history of skindisease or currently undergoing treatment for a dermatologic conditionor who did not respond positively to the soap sensitivity screening testas well as subjects currently within the 2 weeks prior to the startdate, taking antiinflammatory agents are excluded.

Experimental Design

Subjects are required to precondition their skin using the conditioningproduct supplied under normal use conditions. This preconditioningperiod is two weeks in length immediately prior to the onset of thestudy. Use of the preconditioning product will continue throughout thestudy for all bathing and showering.

A group panel of 30 subjects is randomly selected based on an acceptableskin condition score for dryness and erythema established at baseline.The panel is randomly balanced for age and sex and each panelist isassigned a subject number. Laboratory wash treatments are for twomorning sessions and two afternoon sessions over a four day test period.The fifth day includes two morning washes. The time interval betweentreatment and final assessment are standard within the panel.

Visual and tactile assessments are conducted immediately before eachwash treatment to evaluate and compare changes in skin condition. Afinal visual assessment is conducted.

The target site is the volar surface of the forearm from the antecubitalfossa (flex area) to the wrist.

Subjects are supplied with blinded product for all home bathing and areinstructed to avoid washing the test site during the test week.

Wash Procedure

All wash treatments are conducted by a technician. Both forearms arewashed simultaneously taking care to exert equal pressure/force to eacharm. Technicians alternate their treatment groups at each wash interval.

1. Using water maintained at 90° F. each forearm is wet thoroughly fromthe flex area to the wrist.

2. The product is placed on a wet pad and spread over the pad. Thetreated pad is then placed on the designated arm and is then gentlyglided up and down the volar surface of the forearm for two minutes.

3. The arm is rinsed under running water for 30 seconds and patted drygently with a soft disposable towel.

Visual Assessment

A trained skin evaluator conducts all visual assessments. The forearmsare assessed for erythema and dryness immediately prior to each washtreatment. A five point scoring scale (0-4) is used to assess skincondition for both dryness and erythema. Half point increments are usedto denote slight differences between arms or for responses notwarranting a full point increase.

    ______________________________________                                        Dryness            Erythema                                                   ______________________________________                                        0    None              0      None                                            1    Slight flaking    1      Mild erythema                                   2    Moderate flaking/scaling                                                                        2      Moderate confluent                                                            erythema                                        3    Marked scaling, slight                                                                          3      Marked erythema                                      fissuring                                                                4    Severe scaling, fissuring                                                                       4      Deep erythema                                   ______________________________________                                    

Forearms are treated until a grade "3" or greater erythema or drynessdevelops (end point score). Once an end point score is attainedtreatment of both sites is discontinued. The final visual assessment isconducted approximately three hours after the last wash.

The arm wash test described above was run comparing the following twoproducts.

                  TABLE III                                                       ______________________________________                                                        Inventions                                                                             Comparative                                                          Form C   Form B                                               Ingredients       % wt/wt                                                     ______________________________________                                        Sodium Cocoyl Isethionate                                                                       10.95      25                                               Stearic Acid      8.01       10                                               Sodium Soap       2.40       5.5                                              Sodium Alkylbenzenesulfonate                                                                    2.02       1.0                                              Sodium Isethionate                                                                              5.09       2.4                                              TEA Lauryl Sulfate                                                                              5.00       --                                               Propylene Glycol  10.00      --                                               Methylparaben     0.20       --                                               Propylparaben     0.10       --                                               Dowicil 200       0.10       --                                               Fragrance         0.10       0.5                                              Lower Fatty Acid             1.5                                              Miscellaneous solids                                                                            --         1.5                                              & electrolytes                                                                Water             To 100.00  To 100.00                                        ______________________________________                                    

As in Table I, Formulation B represents a 50% slurry of a commercialbar. The percentages are thus approximate.

Formulation C has no guar gum or viscasil.

The test was run to compare the mildness/irritation potential ofcleanser C with a 50% slurry of a commercial bar B.

The test site was treated with one gram of slurry B or 0.5 gram of thefacial cleanser C.

                  TABLE IV                                                        ______________________________________                                        RESULTS OF ARM WASH TEST:                                                     ______________________________________                                                       END POINT    END POINT                                         MEAN SCORES*   ERYTHEMA     DRYNESS                                           ______________________________________                                        Slurry B        1.000        1.531                                            Product C       1.250        1.563                                            ______________________________________                                        MEAN RANK:     ERYTHEMA     DRYNESS                                           ______________________________________                                        Slurry B       13.88        15.81                                             Product C      19.13        17.19                                             STATISTICAL    p = 0.0981   p = 0.6844                                        ANALYSIS OF                                                                   RANK SCORES:                                                                  (Wilcoxon 2 sample)                                                           ______________________________________                                         *Mean end point scores are the mean of the evalutation scores at which th     first arm receives a grade "2" or greater erythema score or grade "3"         dryness score or at the completion of nineteen washes.                   

The results indicated no significant difference (P≦).05) between ProductB slurry and Product C based on the mean rank erythema and drynessscores at end point. Product C was somewhat more irritating than theslurry.

SUMMARY

The inventive composition has been evaluated in clinical studies againsta slurry of a commercial bar.

In the Flex Wash against the slurry, the scores for the inventivecomposition were identical to the slurry scores for erythema. In the ArmWash test, the inventive composition scores for dryness were very closeto those of the slurry. There were some negative differences between theinventive composition scores and the slurry for erythema in the ArmWash.

                  TABLE V                                                         ______________________________________                                                      Slurry                                                                              Inventive Composition                                     ______________________________________                                        Flex Wash Erythema                                                                            1.385   1.385                                                 Arm Wash Dryness                                                                              1.531   1.563                                                 Arm Wash Erythema                                                                             1.000   1.250                                                 ______________________________________                                    

Facial Wash Study

The test group includes 35 subjects/panelists in the age group of 18 to55 years. The subject must have no history of allergies or skindiseases. Panelists must refrain from using facial creams, lotions orother type of moisturizing products on their faces throughout theduration of the test period. Upon admittance to the study, each subjectis provided with (2) bars of commercial soap to be used at home for atwo week period prior to the start of testing.

Eligible panelists are assigned test products selected at random toequal a Right/Left or Left/Right balance in product assignment to eachhalf-face side. Assigned Groups Include:

    ______________________________________                                        Group I            Group II                                                   ______________________________________                                        Right half, Code B Right half, Code A                                         Left half, Code A  Left half, Code B                                          ______________________________________                                    

Procedure

The schedule of wash treatments includes a single facial wash conductedboth in the morning and afternoon and for four consecutive test days ora total of 7 wash treatments. Panelists are instructed not to useanything on their faces except to wash with warm water and face cloth.

Each subject has their face washed in the following manner by atechnician:

a) Wet both sides of the face 10 seconds

b) An abundant lather is worked up for each test product for 10 secondsby gently rubbing a moistened pad (95°-100° F.) made of soft non-wovencotton cloth in each product.

c) The lathered pads are then massaged slowly but firmly over the cheekarea using a counter-circular motion with a pad in each hand, washingfor 60 seconds then rinsing with running water (95°-100° F.) for 10seconds. This procedure is repeated a second time to equal a two-minutewash treatment. The face is then rinsed for 60 seconds with warm waterand patted dry using soft disposable terry towels.

Evaluation and Scouring System

a) Panelist self-assessment of facial skin condition is conducted onceduring the study.

b) Panelist will assess their facial condition based on a globalevaluation of appearance and feel of skin, comparing both left and rightsides of the face.

c) Trained assessors also assess the skin condition using a grade scorescale ranging from 0 to 2.5; independent parameters of evaluation willinclude softness and feel, degree of dryness, etythema and roughness ofthe face.

d) Panelists and trained assessors assess both sides of their face withthe same hand at all times. The inside forearm of the opposite arm willrepresent a reference control site for softness.

Data and Statistics

The raw data scores are analyzed employing a paired t-test andparametric statistical design.

A half face test was conducted as described above on 35 panelists with"normal" skin types to compare the formulation of the invention and acommercial liquid soap. After one week screening period, the test periodconsisted of 8 wash treatments over a 4 day span with 9 evaluationsdone. The first evaluation was made prior to the first wash treatment ofthe ninth evaluation was made on the morning of the fifth day. Thepanelists have refrained from the use of anything but water on theirfaces during the study. Evaluations of various attributes were made byone expert judge and each panelist over the test period.

The top line results of this study are summarized in Table VI. The tableindicates those evaluations for which statistically significantdifferences (with 95% confidence) were detected for each of the expertjudge and panelist questions.

The composition A specified in Table I was compared to a commercialliquid soap with the following results.

                  TABLE VI                                                        ______________________________________                                        Results of Facial Wash                                                                Judges*             Panelists*                                                Compo-   Commercial Compo-  Commercial                                Attribute                                                                             sition A Liquid     sition A                                                                              Liquid                                    ______________________________________                                        Overall 24**     1          17**    4                                         Softness                                                                      Erythema                                                                              26.1**   40.9                                                         Dryness 23.4**   43.6       3.6**   5.1                                       Roughness                                                                             22.7**   44.3       3.4**   4.9                                       Tightness                   3.0**   4.1                                       Burning                     2.1**   3.3                                       Stinging                    2.2**   2.9                                       Itching                     2.9**   3.6                                       ______________________________________                                         *The judges scores reflect mean ranks for all panelists. The panelists        scores are individual scores based on a 0-9 scale.                            **Significant at the 95% confidence level. In the Half Face test against      the Commercial Liquid, Composition A is significantly (95% confidence         level) preferred by both judges and panelists for overall softness. The       judges also rated the Composition A significantly (95% confidence level)      better than the Commercial Liquid for dryness, roughness, tightness,          burning, itching and stinging.                                           

This invention has been described with respect to certain preferredembodiments and various modifications and variations in the lightthereof will be suggested to persons skilled in the art and are to beincluded within the spirit and purview of this application and the scopeof the appended claims.

What is claimed is:
 1. A liquid aqueous based skin cleansing compositionconsisting essentially of:i) 3% to 20% acyl esters of isethionic acidsalts, said esters being predominantly C₈ -C₂₂ acyl isethionates; ii) 2%to 15% of at least one long chain fatty acid having a major proportionof C₁₆ or above; iii) 2% to 20% of co-surfactant selected from the groupconsisting of alkyl ether sulfates, alkyl ether sulfonates,sarcosinates, sulfosuccinates, taurates, alkylbetaines,amidopropylbetaines, amidopropyl sultaines alkyl sulfonates, alkylsulfate and mixtures thereof and iv) 2% to 15% of a moisturizercomponent, wherein the weight ratio of said acyl esters to fatty acidranges from about 1:0.1 to about 1:10, and soap is present in an amountfrom 0 to 5% by weight of the composition, said composition having aviscosity of about 100 to about 30,000 cps.
 2. A composition accordingto claim 1 wherein the co-surfactant is selected from the groupconsisting of alkyl ether sulfates, alkyl sulfonates, and mixturesthereof.
 3. A composition according to claim 1 wherein the co-surfactantis an alkyl sulfate.
 4. A composition according to claim 3 wherein themoisturizer is propylene glycol.
 5. A composition according to claim 1containing about 1% to 7% of sodium isethionate.
 6. A compositionaccording to claim 1 having a viscosity of about 10,000 cps.
 7. A liquidaqueous based skin cleansing composition having a formulation consistingessentially of:

    ______________________________________                                        Ingredients              %                                                    ______________________________________                                        Sodium cocoyl isethionate                                                                               11%                                                 A mixture of about 55% Palmitic                                                                         8%                                                  acid and about 45% Stearic acid                                               Propylene glycol          10%                                                 Sodium isethionate        5%                                                  TEA lauryl sulfate        5%                                                  Sodium soap               2.5%                                                Sodium alkylbenzene       2%                                                  sulfonate                                                                     Fragrance                 0.4%                                                p hydroxy methyl benzoate                                                                               0.20%                                               p hydroxy propyl benzoate                                                                               0.10%                                               N-(3 chloroallyl) Hexaminium                                                                            0.10%                                               chloride                                                                      EDTA                      0.20%                                               EHDP                      0.20%                                               BHT                       0.008%                                              Water to                 100.00%                                              ______________________________________                                    

said composition having a viscosity of about 100 to about 30,000 cps. 8.A liquid aqueous based skin cleansing composition having a formulationconsisting essentially of:

    ______________________________________                                        Ingredients          %                                                        ______________________________________                                        Sodium cocoyl isethionate                                                                           3 to 20%                                                A mixture of about 55% Palmitic                                                                     2 to 15%                                                acid and about 45% Stearic acid                                               Propylene glycol      5 to 15%                                                Sodium isethionate   1 to 8%                                                  TEA lauryl sulfate   1 to 8%                                                  Sodium soap          1 to 5%                                                  Sodium alkylbenzene sulfonate                                                                      1 to 5%                                                  p hydroxy methyl benzoate                                                                          0.1 to 1%                                                p hydroxy propyl benzoate                                                                          0.1 to 1%                                                N-(3 choroally) Hexaminium                                                                         0.1 to 1%                                                chloride                                                                      EDTA                 0.01 to 0.5%                                             EHDP                 0.01 to 0.5%                                             BHT                  0.01 to 1.0%                                             ______________________________________                                    

said composition having a viscosity of about 100 to about 30,000 cps. 9.A composition according to claim 1 wherein said co-surfactant is amixture of disodium Cocoamido MEA Sulfosuccinate and Disodium oleamidoMEA Sulfosuccinate.
 10. A liquid aqueous based skin cleansingcomposition having a formulation consisting essentially of:

    ______________________________________                                        Ingredients         %                                                         ______________________________________                                        long chain acylisethionate                                                                         3 to 20%                                                 A mixture of about 55% Palmitic                                                                    2 to 15%                                                 acid and about 45% Stearic acid                                               Propylene glycol     5 to 15%                                                 Sodium isethionate  1 to 8%                                                   Co-surfactant        2 to 20%                                                 Sodium soap         1 to 5%                                                   Sodium alkylbenzene                                                           sulfonate           1 to 5%                                                   Preservative        0.1 to 1%                                                 sequesterant        0.01 to 0.1%                                              ______________________________________                                    

said composition having a viscosity of about 100 to about 30,000 cps.said co-surfactant being selected from the group consisting of alkylether sulfates, alkyl ether sulfonates, sarcosinates, sulfosuccinates,taurates, alkylbetaines, amidopropylbetaines, amidopropyl sultaines,alkyl sulfonates, alkyl sulfates and mixtures thereof.
 11. A compositionaccording to claim 10 wherein said co-surfactant is selected from thegroup consisting of alkyl ether sulfates, alkyl ether sulfonates,sarcosinates, sulfosuccinates, taurates, alkylbetaines,amidopropylbetaines, amidopropyl sultaines and mixtures thereof.
 12. Acomposition according to claim 11:wherein said alkyl ether sulfate isselected from the group consisting of sodium laureth sulfate, TEAlaureth sulfates, sodium laureth 12 sulfate, sodium trideceth sulfateand mixtures thereof; wherein said sulfosuccinates are selected from thegroup consisting of disodium lauryl sulfosuccinate, disodium cocamidoMEA sulfosuccinate, disodium myristamido MEA sulfosuccinate, disodiumoleamido MEA sulfosuccinate, disodium ricinoleamido MEA sulfosuccinateand mixtures thereof; wherein said sarcosinates are selected from thegroup consisting of sodium lauroyl sarcosinate, TEA cocoyl sarcosinateand mixtures thereof; wherein said taurates are selected from the groupconsisting of sodium methyl cocoyl taurate, sodium methyl oleoyl taurateand mixtures thereof; wherein said alkyl betaines are selected from thegroup consisting of cocobetaine, oleyl betaine and mixtures thereof;wherein said amidopropylbetaines are selected from the group consistingof cocoamidopropyl betaine, myristamidopropyl betaine and mixturesthereof; and wherein said amidopropyl sultaine is cocoamidopropylhydroxysultaine.
 13. A composition according to claim 1:wherein saidalkyl ether sulfate is selected from the group consisting of sodiumlaureth sulfate, TEA laureth sulfates, sodium laureth 12 sulfate, sodiumtrideceth sulfate and mixtures thereof; wherein said sulfosuccinates areselected from the group consisting of disodium lauryl sulfosuccinate,disodium cocamido MEA sulfosuccinate, disodium myristamido MEAsulfosuccinate, disodium oleamido MEA sulfosuccinate, disodiumricinoleamido MEA sulfosuccinate and mixtures thereof; wherein saidsarcosinates are selected from the group consisting of sodium lauroylsarcosinate, TEA cocoyl sarcosinate and mixtures thereof; wherein saidtaurates are selected from the group consisting of sodium methyl cocoyltaurate, sodium methyl oleoyl taurate and mixtures thereof; wherein saidalkyl betaines are selected from the group consisting of cocobetaine,oleyl betaine and mixtures thereof; wherein said amidopropylbetaines areselected from the group consisting of cocoamidopropyl betaine,myristamidropropyl betaine and mixtures thereof; and wherein saidamidopropyl sultaine is cocoamidopropyl hydroxysultaine.